1. Field of the Invention
Embodiments of the present invention relate to a frame structure for a vehicle seat. Preferably, the frame structure has two frames extending in a specific direction and integrally connected together.
2. Description of the Related Art
Japanese Laid-Open Patent Publication No. 2012-218665 discloses a frame structure for a vehicle seat. The frame structure has a side frame for a seatback. The side frame has a side frame main body formed of a thin steel plate and a sub frame formed of a thick steel plate, with the two frames being connected to each other in the height direction. The side frame main body and the sub frame are butt-welded to each other in the height direction. Another frame is passed astride the side frame main body and the sub frame. Since another frame is provided between the side frame main body and the sub frame, it is possible to suppress an abrupt change in the section modulus between them.
As a result, a reduction in structural strength is prevented, and the bonding strength for the side frame main body and the sub frame is enhanced. It should be noted, however, that end portions of frames differing in thickness are butt-welded to each other. Thus, it is rather difficult to perform positioning of the frame which makes the structure difficult to produce.
Therefore, there is a need in the art for a frame structure light in weight and providing high strength and easy to produce.